Owing to the rapidly improvement of manufacturing technique many portable electronic devices are changed to be smaller, lighter, thinner and more elaborate than before so as to increase the convenience for people to use. For example, a mobile phone or a PDA (personal digital assistant) is developed to perform wireless communication and transmit data more efficiently when people need to store a personal information immediately. Thus, the portable electronic devices have become the necessaries in modern life.
When the portable electronic devices have become smaller, the size of the interface of the portable electronic devices are required to be, which will often causes great inconvenience for inputting data. For example, a touchable screen in a conventional PDA device is the customarily used input device for people to input data into the PDA. In addition, cause the keypads on the mobile phone is smaller than before, the users could frequently press the keypad by mistake. Thus, the input interface constructed in the mobile phone need to be reduced either, which also causes inconvenience.
Therefore, it is an attempt by the applicant to provide an external input device to solve the problems as described above and an easy-operated external data-input device for people to input the data into the portable electronic device.